For the un-initiated, 'Oysters' are a London thing. No, it's not a deep-seated love of expensive bivalve mollusks, merely the the crazy-spectacular name for bus/train pass, available from London Transport.

(Personally, I think they called it that because they planned it to go in a holder like this and they think that opening up the 'shell like' holder reveals the 'pearl' of a card inside. What do you think? Have I over thought this? Have you ever travelled in London? Believe me, there's a lot of time for thought.)

actually, they do rip quite easily, as carlyinvailn says - they're not as good as they look! If you're visiting London though, you could ask at a tube station, say you need one for your Oyster card - and look needy - and they might give you one :)

Oh... well, I won't be in London any time soon, alas (one of my favorite places in the world, too) so maybe I'll buy the one with the Tube map attached that someone's selling on eBay, to go along with the Tube map I have framed on the wall. :)

not really. They have a protective laminate on them and it's pretty hardy. Mine have been on there since last summer and they're doing ok (I use the card every day). It will get a bit scuffed over time, but certainly not immediately.

Of course, any railcard and/or season ticket holder (National Rail, etc.), bus pass, and even the freeby credit card holders from some banks and building societies (I know Nat West used to give them out for free) would take this method of enhancement. ;-p